1 CCNA Security Chapter Five Implementing Intrusion Prevention

1

CCNA Security

Chapter Five

Implementing Intrusion Prevention

222

Lesson Planning

• This lesson should take 3-6 hours to present

• The lesson should include lecture,

demonstrations, discussion and assessments

• The lesson can be taught in person or using

remote instruction

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Major Concepts

• Describe the purpose and operation of network-based and host-based Intrusion Prevention Systems (IPS)

• Describe how IDS and IPS signatures are used to detect malicious network traffic

• Implement Cisco IOS IPS operations using CLI and SDM

• Verify and monitor the Cisco IOS IPS operations using CLI and SDM

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Contents

• 5.1 IPS Technologies

• 5.2 IPS Signatures

• 5.3 Implementing IPS

• 5.4 Verify and Monitor IPS

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5.1 IPS Technologies

Chapter Five


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IPS Technologies

• Introduction to IDS and IPS

• IPS Implementations

• Network-Based IPS Implementations

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5.1.1 IDS and IPS Characteristics

• Common Intrusions

• Intrusion Detection Systems

• Intrusion Prevention Systems

• Common Characteristics of IDS and IPS

• Comparing IDS and IPS Solutions

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Common Intrusions

MARS

Remote Worker

Remote BranchVPN

VPN

VPN

ACS

Iron Port

Firewall

Web Server

Email Server DNS

LANCSA

Zero-day exploit attacking the network

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Intrusion Detection Systems (IDSs)

1. An attack is launched on a network that has a sensor deployed in promiscuous IDS mode; therefore copies of all packets are sent to the IDS sensor for packet analysis. However, the target machine will experience the malicious attack.

2. The IDS sensor, matches the malicious traffic to a signature and sends the switch a command to deny access to the source of the malicious traffic.

3. The IDS can also send an alarm to a management console for logging and other management purposes.

Switch

Management Console

1

2

3

Target

Sensor

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Intrusion Prevention Systems (IPSs)

1. An attack is launched on a network that has a sensor deployed in IPS mode (inline mode).

2. The IPS sensor analyzes the packets as they enter the IPS sensor interface. The IPS sensor matches the malicious traffic to a signature and the attack is stopped immediately.

3. The IPS sensor can also send an alarm to a management console for logging and other management purposes.

4. Traffic in violation of policy can be dropped by an IPS sensor.

Sensor

Management Console

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2

3

Target

4

Bit Bucket

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Common characteristics of IDS and IPS

Both technologies are deployed using sensors.

Both technologies use signatures to detect patterns of misuse in network traffic.

Both can detect atomic patterns (single-packet) or composite patterns (multi-packet).

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Comparing IDS and IPS Solutions

Advantages Disadvantages

No impact on network (latency, jitter)

No network impact if there is a sensor failure

No network impact if there is sensor overload

Response action cannot stop trigger packets

Correct tuning required for response actions

Must have a well thought-out security policy

More vulnerable to network evasion techniques

IDS

Pro

miscu

ous

Mo

de

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Comparing IDS and IPS Solutions


Stops trigger packets

Can use stream normalization techniques

Sensor issues might affect network traffic

Sensor overloading impacts the network

Must have a well thought-out security policy

Some impact on network (latency, jitter)

IPS

Inline

Mo

de

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5.1.2 Host-Based IPS Implementations

• Types of Implementations

• Cisco Security Agent

• Cisco Security Agent Screens

• Host-Based Solutions

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Network-Based Implentation

MARS

Remote Worker

Remote BranchVPN

VPN

VPN

Iron Port

Firewall

Web Server

Email Server DNS

IPS

CSACSA CSA

CSA

CSA

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Host-Based Implementation

MARS

Remote Worker

Remote BranchVPN

VPN

VPN

Iron Port

Firewall

IPS

CSA

CSA

Web Server

Email Server DNS

CSACSA CSA

CSA

CSA

CSA

CSA

Agent

Management Center for Cisco Security Agents

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Firewall

CorporateNetwork

DNSServer

WebServer

Cisco Security Agent

Management Center for Cisco Security Agents

SMTPServer

ApplicationServer

Agent

AgentAgent

Agent

AgentAgent

UntrustedNetwork

Agent

AgentAgent

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A waving flag in the system tray indicates a potential security problem.

CSA maintains a log file allowing the user to verify problems and learn more information.

Cisco Security Agent Screens

A warning message appears when CSA detects a Problem.

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Host-Based Solutions

Advantages Disadvantages The success or failure of an

attack can be readily determined.

HIPS does not have to worry about fragmentation attacks or variable Time to Live (TTL) attacks.

HIPS has access to the traffic in unencrypted form.

HIPS does not provide a complete network picture.

HIPS has a requirement to support multiple operating systems.

Advantages and Disadvantages of HIPS

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5.1.3 Network-Based IPS Implementations

• Network-Based Solutions

• Cisco IPS Solutions

• IPS Sensors

• Comparing HIPS and Network IPS

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Network-Based Solutions

ManagementServer

CorporateNetwork

DNSServer

WebServer

Sensor

Sensor

Firewall

Sensor

RouterUntrustedNetwork

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Cisco IPS SolutionsAIM and Network Module Enhanced

• Integrates IPS into the Cisco 1841 (IPS AIM only), 2800 and 3800 ISR routers (IPS NME)

• IPS AIM occupies an internal AIM slot on router and has its own CPU and DRAM

• Monitors up to 45 Mb/s of traffic

• Provides full-featured intrusion protection

• Is able to monitor traffic from all router interfaces

• Can inspect GRE and IPsec traffic that has been decrypted at the router

• Delivers comprehensive intrusion protection at branch offices, isolating threats from the corporate network

• Runs the same software image as Cisco IPS Sensor Appliances

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Cisco IPS SolutionsASA AIP-SSM

• High-performance module designed to provide additional security services to the Cisco ASA 5500 Series Adaptive Security Appliance

• Diskless design for improved reliability

• External 10/100/1000 Ethernet interface for management and software downloads

• Intrusion prevention capability

• Runs the same software image as the Cisco IPS Sensor appliances

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Cisco IPS Solutions4200 Series Sensors

• Appliance solution focused on protecting network devices, services, and applications

• Sophisticated attack detection is provided.

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Cisco IPS Solutions Cisco Catalyst 6500 Series IDSM-2

• Switch-integrated intrusion protection module delivering a high-value security service in the core network fabric device

• Support for an unlimited number of VLANs

• Intrusion prevention capability

• Runs the same software image as the Cisco IPS Sensor Appliances

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IPS Sensors

• Factors that impact IPS sensor selection and deployment:

- Amount of network traffic

- Network topology

- Security budget

- Available security staff to manage IPS

• Size of implementation- Small (branch offices)

- Large

- Enterprise

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Comparing HIPS and Network IPS


HIPS

Is host-specific

Protects host after decryption

Provides application-level encryption protection

Operating system dependent

Lower level network events not seen

Host is visible to attackers

Network IPS

Is cost-effective

Not visible on the network

Operating system independent

Lower level network events seen

Cannot examine encrypted traffic

Does not know whether an attack was successful

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5.2 IPS Signatures

Chapter Five


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IPS Signatures

• IPS Signature Characteristics

• IPS Signature Alarms

• Tuning IPS Signature Alarms

• Implementing IPS

• IPS Signature Monitoring

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5.2.1 IPS Signature Characteristics

• Introduction

• Signature Types

• Signature Files

• Signature Micro-engines

• Cisco Signature List

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Introduction

Hey, come look at this.

This looks like the signature

of a LAND attack.

• An IDS or IPS sensor matches a signature with a data flow

• The sensor takes action

• Signatures have three distinctive attributes

- Signature type

- Signature trigger

- Signature action

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Signature Types

• Atomic- Simplest form

- Consists of a single packet, activity, or event

- Does not require intrusion system to maintain state information

- Easy to identify

• Composite- Also called a stateful signature

- Identifies a sequence of operations distributed across multiple hosts

- Signature must maintain a state known as the event horizon

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Signature File

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Version 4.x

SME Prior 12.4(11)T

Version 5.x

SME 12.4(11)T and laterDescription

ATOMIC.IP ATOMIC.IP Provides simple Layer 3 IP alarms

ATOMIC.ICMP ATOMIC.IPProvides simple Internet Control Message Protocol (ICMP) alarms based on the following parameters: type, code, sequence, and ID

ATOMIC.IPOPTIONS ATOMIC.IP Provides simple alarms based on the decoding of Layer 3 options

ATOMIC.UDP ATOMIC.IPProvides simple User Datagram Protocol (UDP) packet alarms based on the following parameters: port, direction, and data length

ATOMIC.TCP ATOMIC.IP Provides simple TCP packet alarms based on the following parameters: port, destination, and flags

SERVICE.DNS SERVICE.DNS Analyzes the Domain Name System (DNS) service

SERVICE.RPC SERVICE.RPC Analyzes the remote-procedure call (RPC) service

SERVICE.SMTP STATE Inspects Simple Mail Transfer Protocol (SMTP)

SERVICE.HTTP SERVICE.HTTP Provides HTTP protocol decode-based string engine that includes ant evasive URL de-obfuscation

SERVICE.FTP SERVICE.FTP Provides FTP service special decode alarms

STRING.TCP STRING.TCP Offers TCP regular expression-based pattern inspection engine services

STRING.UDP STRING.UDP Offers UDP regular expression-based pattern inspection engine services

STRING.ICMP STRING.ICMP Provides ICMP regular expression-based pattern inspection engine services

MULTI-STRING MULTI-STRING Supports flexible pattern matching and supports Trend Labs signatures

OTHER NORMALIZER Provides internal engine to handle miscellaneous signatures

Signature Micro-Engines

Atomic – Examine simple packets

Service – Examine the many services that are attacked

String – Use expression-based patterns to detect intrusions

Multi-String Supports flexible pattern matching

Other – Handles miscellaneous signatures

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Cisco Signature List

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5.2.2 IPS Signature Alarms

• Signature Triggers

- Pattern-based Detection

- Anomaly-based Detection

- Policy-based Detection

- Honey Pot-based Detection

• Cisco IOS IPS Solution Benefits

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Signature Triggers


Pattern-basedDetection

• Easy configuration

• Fewer false positives

• Good signature design

• No detection of unknown signatures

• Initially a lot of false positives

• Signatures must be created, updated, and tuned

Anomaly-based

Detection

• Simple and reliable

• Customized policies

• Can detect unknown attacks

• Generic output

• Policy must be created

Policy-basedDetection

• Easy configuration

• Can detect unknown attacks

• Difficult to profile typical activity in large networks

• Traffic profile must be constant

Honey Pot-Based

Detection

• Window to view attacks

• Distract and confuse attackers

• Slow down and avert attacks

• Collect information about attack

• Dedicated honey pot server

• Honey pot server must not be trusted

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Pattern-based Detection

Trigger Signature Type

Atomic Signature Stateful Signature

Pattern-based

detection

No state required to examine pattern to determine if signature action should be applied

Must maintain state or examine multiple items to determine if signature action should be applied

Example

Detecting for an Address Resolution Protocol (ARP) request that has a source Ethernet address of FF:FF:FF:FF:FF:FF

Searching for the string confidential across multiple packets in a TCP session

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Anomaly-based Detection

Trigger Signature Type


Anomaly-based

detection

No state required to identify activity that deviates from normal profile

State required to identify activity that deviates from normal profile

Example

Detecting traffic that is going to a destination port that is not in the normal profile

Verifying protocol compliance for HTTP traffic

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Policy-based Detection

Signature Trigger

Signature Type


Policy-based

detection

No state required to identify undesirable behavior

Previous activity (state) required to identify undesirable behavior

Example

Detecting abnormally large fragmented packets by examining only the last fragment

A SUN Unix host sending RPC requests to remote hosts without initially consulting the SUN PortMapper program.

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Honey Pot-based Detection

• Uses a dummy server to attract attacks

• Distracts attacks away from real network devices

• Provides a means to analyze incoming types of attacks and malicious traffic patterns

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Cisco IOS IPS Solution Benefits

• Uses the underlying routing infrastructure to provide an additional layer of security with investment protection

• Attacks can be effectively mitigated to deny malicious traffic from both inside and outside the network

• Provides threat protection at all entry points to the network when combined with other Cisco solutions

• Is supported by easy and effective management tools

• Offers pervasive intrusion prevention solutions that are designed to integrate smoothly into the network infrastructure and to proactively protect vital resources

• Supports approximately 2000 attack signatures from the same signature database that is available for Cisco IPS appliances

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5.2.3 Tuning IPS Signature Alarms

• Signature Alarms

• Signature Tuning Levels

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Signature Alarms

Alarm Type Network Activity IPS Activity Outcome

False positive Normal user trafficAlarm

generatedTune alarm

False negative Attack trafficNo alarm generated

Tune alarm

True positive Attack trafficAlarm

generatedIdeal

setting

True negative Normal user trafficNo alarm generated

Ideal setting

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Signature Tuning Levels

Low – Abnormal network activity is detected, couldbe malicious, and immediate threat is not likely

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Medium - Abnormal network activity is detected, couldbe malicious, and immediate threat is likely

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High – Attacks used to gain access or cause a DoSattack are detected (immediate threat extremely likely

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Informational – Activity that triggers the signatureis not an immediate threat, but the information provided is useful

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5.2.4 Signature Actions

• Generating an alert

• Logging the activity

• Dropping or preventing the activity

• Resetting a TCP connection

• Blocking future activity

• Allowing the activity

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Generating an Alert

Specific Alert

Description

Produce alertThis action writes the event to the Event Store as an alert.

Produce verbose alert

This action includes an encoded dump of the offending packet in the alert.

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Logging the Activity

Specific Alert Description

Log attacker packets

This action starts IP logging on packets that contain the attacker address and sends an alert.

Log pair packetsThis action starts IP logging on packets that contain the attacker and victim address pair.

Log victim packets

This action starts IP logging on packets that contain the victim address and sends an alert.

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Dropping/Preventing the Activity

Specific Alert Description

Deny attacker inline

• Terminates the current packet and future packets from this attacker address for a period of time.

• The sensor maintains a list of the attackers currently being denied by the system.

• Entries may be removed from the list manually or wait for the timer to expire.

• The timer is a sliding timer for each entry.

• If the denied attacker list is at capacity and cannot add a new entry, the packet is still denied.

Deny connection inline

•Terminates the current packet and future packets on this TCP flow.

Deny packet inline

•Terminates the packet.

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CategorySpecific

AlertDescription

Resetting a TCP

connection

Reset TCP connection

•Sends TCP resets to hijack and terminate the TCP flow

Blocking future

activity

Request block connection

•This action sends a request to a blocking device to block this connection.

Request block host

•This action sends a request to a blocking device to block this attacker host.

Request SNMP trap

•Sends a request to the notification application component of the sensor to perform SNMP notification.

Allowing Activity

•Allows administrator to define exceptions to configured signatures

Resetting a TCP Connection/BlockingActivity/Allowing Activity

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5.2.5 Signature Monitoring

• Planning a Monitoring Strategy

• Cisco MARS

• Cisco IPS Solutions

• Secure Device Event Exchange

• Best Practices

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Planning a Monitoring Strategy

The MARS appliance

detected and mitigated the ARP poisoning

attack.

There are four factors to consider when planning a monitoring strategy.• Management method• Event correlation• Security staff• Incident response plan

There are four factors to consider when planning a monitoring strategy.• Management method• Event correlation• Security staff• Incident response plan

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MARS

The security operator examines the output generated by the MARS appliance:• MARS is used to centrally

manage all IPS sensors. • MARS is used to correlate all

of the IPS and Syslog events in a central location.

• The security operator must proceed according to the incident response plan identified in the Network Security Policy.

The security operator examines the output generated by the MARS appliance:• MARS is used to centrally

manage all IPS sensors. • MARS is used to correlate all

of the IPS and Syslog events in a central location.

• The security operator must proceed according to the incident response plan identified in the Network Security Policy.

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Cisco IPS Solutions

• Locally Managed Solutions:

- Cisco Router and Security Device Manager (SDM)

- Cisco IPS Device Manager (IDM)

• Centrally Managed Solutions:

- Cisco IDS Event Viewer (IEV)

- Cisco Security Manager (CSM)

- Cisco Security Monitoring, Analysis, and Response System (MARS)

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Cisco Router and Security Device Manager

Lets administrators control the application of Cisco IOS IPS on interfaces, import and edit signature definition files (SDF) from Cisco.com, and configure the action that Cisco IOS IPS is to take if a threat is detected

Monitors and prevents intrusions by comparing traffic against signatures of known threats and blocking the traffic when a threat is detected

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Cisco IPS Device Manager

• A web-based configuration tool

• Shipped at no additional cost with the Cisco IPS Sensor Software

• Enables an administrator to configure and manage a sensor

• The web server resides on the sensor and can be accessed through a web browser

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Cisco IPS Event Viewer

• View and manage alarms for up to five sensors

• Connect to and view alarms in real time or in imported log files

• Configure filters and views to help you manage the alarms.

• Import and export event data for further analysis.

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Cisco Security Manager

• Powerful, easy-to-use solution to centrally provision all aspects of device configurations and security policies for Cisco firewalls, VPNs, and IPS

• Support for IPS sensors and Cisco IOS IPS

• Automatic policy-based IPS sensor software and signature updates

• Signature update wizard

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Cisco Security Monitoring Analyticand Response System

• An appliance-based, all-inclusive solution that allows network and security administrators to monitor, identify, isolate, and counter security threats

• Enables organizations to more effectively use their network and security resources.

• Works in conjunction with Cisco CSM.

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Secure Device Event Exchange

• The SDEE format was developed to improve communication of events generated by security devices

• Allows additional event types to be included as they are defined

Network Management

ConsoleAlarm

SDEE Protocol

Syslog Server

AlarmSyslog

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Best Practices

• The need to upgrade sensors with the latest signature packs must be balanced against the momentary downtime.

• When setting up a large deployment of sensors, automatically update signature packs rather than manually upgrading every sensor.

• When new signature packs are available, download the new signature packs to a secure server within the management network. Use another IPS to protect this server from attack by an outside party.

• Place the signature packs on a dedicated FTP server within the management network. If a signature update is not available, a custom signature can be created to detect and mitigate a specific attack.

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Best Practices

• Configure the FTP server to allow read-only access to the files within the directory on which the signature packs are placed only from the account that the sensors will use.

• Configure the sensors to automatically update the signatures by checking the FTP server for the new signature packs periodically. Stagger the time of day when the sensors check the FTP server for new signature packs.

• The signature levels that are supported on the management console must remain synchronized with the signature packs on the sensors themselves.

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5.3 Implementing IPS

Chapter Five


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Implementing IPS

• Configuring Cisco IOS IPS with CLI

• Configuring Cisco IOS IPS with SDM

• Modifying Cisco IOS IPS Signatures

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5.3.1 Configuring Cisco IOS IPS with CLI

1. Download the IOS IPS files

2. Create an IOS IPS configuration directory on Flash

3. Configure an IOS IPS crytpo key

4. Enable IOS IPS

5. Load the IOS IPS Signature Package to the router

I want to use CLI to manage my signature

files for IPS. I have downloaded the IOS

IPS files.

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1. Download the Signature File

Download IOS IPSsignature package filesand public crypto key

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2. Create Directory

R1# mkdir ipsCreate directory filename [ips]?Created dir flash:ipsR1#R1# dir flash:Directory of flash:/ 5 -rw- 51054864 Jan 10 2009 15:46:14 -08:00 c2800nm-advipservicesk9-mz.124-20.T1.bin 6 drw- 0 Jan 15 2009 11:36:36 -08:00 ips64016384 bytes total (12693504 bytes free)R1#

R1# rename ips ips_newDestination filename [ips_new]?R1#

To rename a directory:

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3. Configure the Crypto Key

R1# conf tR1(config)#

1

2

1 – Highlight and copy the text contained in the public key file.

2 – Paste it in global configuration mode.

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Confirm the Crypto Key

R1# show run

<Output omitted>

crypto key pubkey-chain rsanamed-key realm-cisco.pub signaturekey-string30820122 300D0609 2A864886 F70D0101 01050003 82010F00 3082010A 0282010100C19E93 A8AF124A D6CC7A24 5097A975 206BE3A2 06FBA13F 6F12CB5B 4E441F1617E630D5 C02AC252 912BE27F 37FDD9C8 11FC7AF7 DCDD81D9 43CDABC3 6007D128B199ABCB D34ED0F9 085FADC1 359C189E F30AF10A C0EFB624 7E0764BF 3E53053E5B2146A9 D7A5EDE3 0298AF03 DED7A5B8 9479039D 20F30663 9AC64B93 C0112A35FE3F0C87 89BCB7BB 994AE74C FA9E481D F65875D6 85EAF974 6D9CC8E3 F0B08B8550437722 FFBE85B9 5E4189FF CC189CB9 69C46F9C A84DFBA5 7A0AF99E AD768C36006CF498 079F88F8 A3B3FB1F 9FB7B3CB 5539E1D1 9693CCBB 551F78D2 892356AE2F56D826 8918EF3C 80CA4F4D 87BFCA3B BFF668E9 689782A5 CF31CB6E B4B094D3F3020301 0001

<Output omitted>

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4. Enable IOS IPS

R1(config)# ip ips name iosipsR1(config)# ip ips name ips list ?<1-199> Numbered access listWORD Named access listR1(config)#R1(config)# ip ips config location flash:ipsR1(config)#

2 – IPS location in flash identified

1

2

R1(config)# ip http server R1(config)# ip ips notify sdeeR1(config)# ip ips notify logR1(config)#

3 – SDEE and Syslog notification are enabled

3

1 – IPS rule is created

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4. Enable IOS IPS

R1(config)# ip ips signature-categoryR1(config-ips-category)# category allR1(config-ips-category-action)# retired trueR1(config-ips-category-action)# exitR1(config-ips-category)# R1(config-ips-category)# category ios_ips basicR1(config-ips-category-action)# retired falseR1(config-ips-category-action)# exitR1(config-ips-category)# exitDo you want to accept these changes? [confirm] yR1(config)#

2 – The IPS basic category is unretired.

1

2

R1(config)# interface GigabitEthernet 0/1R1(config-if)# ip ips iosips inR1(config-if)# exitR1(config)#exit

R1(config)# interface GigabitEthernet 0/1R1(config-if)# ip ips iosips inR1(config-if)# ip ips iosips outR1(config-if)# exitR1(config)# exit 4 – The IPS rule is applied in an incoming and outgoing

direction.

3

4

1 – The IPS all category is retired

3 – The IPS rule is applied in a incoming direction

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5. Load Signature Package

R1# copy ftp://cisco:[email protected]/IOS-S376-CLI.pkg idconfLoading IOS-S310-CLI.pkg !!!!!!!!!!!!!!!!!!!!!!!!!!!!!![OK - 7608873/4096 bytes]*Jan 15 16:44:47 PST: %IPS-6-ENGINE_BUILDS_STARTED: 16:44:47 PST Jan 15 2008*Jan 15 16:44:47 PST: %IPS-6-ENGINE_BUILDING: multi-string - 8 signatures - 1 of 13 engines*Jan 15 16:44:47 PST: %IPS-6-ENGINE_READY: multi-string - build time 4 ms - packets for this engine will be scanned*Jan 15 16:44:47 PST: %IPS-6-ENGINE_BUILDING: service-http - 622 signatures - 2 of 13 engines*Jan 15 16:44:53 PST: %IPS-6-ENGINE_READY: service-http - build time 6024 ms - packets for this engine will be scanned

<Output omitted>

*Jan 15 16:45:18 PST: %IPS-6-ENGINE_BUILDING: service-smb-advanced - 35 signatures - 12 of 13 engines*Jan 15 16:45:18 PST: %IPS-6-ENGINE_READY: service-smb-advanced - build time 16 ms - packets for this engine will be scanned*Jan 15 16:45:18 PST: %IPS-6-ENGINE_BUILDING: service-msrpc - 25 signatures - 13 of 13 engines*Jan 15 16:45:18 PST: %IPS-6-ENGINE_READY: service-msrpc - build time 32 ms - packets for this engine will be scanned*Jan 15 16:45:18 PST: %IPS-6-ALL_ENGINE_BUILDS_COMPLETE: elapsed time 31628 ms

2 – Signature compiling begins immediately after the signature package is loaded to the router.

1

2

1 – Copy the signatures from the FTP server.

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Verify the Signature

R1# show ip ips signature countCisco SDF release version S310.0 ← signature package release versionTrend SDF release version V0.0Signature Micro-Engine: multi-string: Total Signatures 8multi-string enabled signatures: 8multi-string retired signatures: 8

<Output omitted>

Signature Micro-Engine: service-msrpc: Total Signatures 25service-msrpc enabled signatures: 25service-msrpc retired signatures: 18service-msrpc compiled signatures: 1service-msrpc inactive signatures - invalid params: 6Total Signatures: 2136Total Enabled Signatures: 807Total Retired Signatures: 1779Total Compiled Signatures: 351 ← total compiled signatures for the IOS IPS Basic categoryTotal Signatures with invalid parameters: 6Total Obsoleted Signatures: 11R1#

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5.3.2 Configuring Cisco IOS IPS in SDM

• Overview

• Using SDM - Fifteen Steps

• SDM IPS Wizard Summary

• Generated CLI Commands

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Overview

Create IPS – this tab contains the IPS Rule wizard

Edit IPS – this tab allows the edit of rules and apply or remove them from interfaces

Security Dashboard– this tab is used to view the Top Threats table and deploy signatures

IPS Migration – this tab is used to migrate configurations created in earlier versions of the IOS

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Using SDM

1. Choose Configure > Intrusion Prevention > Create IPS

2. Click the Launch IPS Rule Wizard button

3. Click Next

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Using SDM

4. Choose the router interface by checking either the Inbound or Outbound checkbox (or both)

5. Click Next

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Using SDM

6. Click the preferred option and fill in the appropriate text box

7. Click download for the latest signature file

8. Go to www.cisco.com/pcgi-bin/tablebuild.pl/ios-v5sigup to obtain the public key

9. Download the key to a PC

10. Open the key in a text editor and copy the text after the phrase “named-key” into the Name field

11. Copy the text between the phrase “key-string” and the work “quit” into the Key field

12. Click Next

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Using SDM

13. Click the ellipsis (…) button and enter config location

14. Choose the category that will allow the Cisco IOS IPS to function efficiently on the router

15. Click finish

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SDM IPS Wizard Summary

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Generated CLI Commands

R1# show run

<Output omitted>

ip ips name sdm_ips_ruleip ips config location flash:/ipsdir/ retries 1ip ips notify SDEE!ip ips signature-category category all retired true category ios_ips basic retired false!interface Serial0/0/0 ip ips sdm_ips_rule in ip virtual-reassembly

<Output omitted>

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5.3.3 Modifying Cisco IOS IPS Signatures

• Using CLI Commands

• Changing the Signature Actions

• Viewing Configured Signatures

• Modifying Signature Actions

• Editing Signature Parameters

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Using CLI Commands

R1# configure terminalEnter configuration commands, one per line. End with CNTL/Z.R1(config)# ip ips signature-definitionR1(config-sigdef)# signature 6130 10R1(config-sigdef-sig)# statusR1(config-sigdef-sig-status)# retired trueR1(config-sigdef-sig-status)# exitR1(config-sigdef-sig)# exitR1(config-sigdef)# exitDo you want to accept these changes? [confirm] yR1(config)#

This example shows how to retire individual signatures. In this case, signature 6130 with subsig ID of 10.

R1# configure terminalEnter configuration commands, one per line. End with CNTL/Z.R1(config)# ip ips signature-categoryR1(config-ips-category)# category ios_ips basicR1(config-ips-category-action)# retired falseR1(config-ips-category-action)# exitR1(config-ips-category)# exitDo you want to accept these changes? [confirm] yR1(config)#

This example shows how to unretire all signatures that belong to the IOS IPS Basic category.

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Using CLI Commands for Changes

R1# configure terminalEnter configuration commands, one per line. End with CNTL/Z.R1(config)# ip ips signature-definitionR1(config-sigdef)# signature 6130 10R1(config-sigdef-sig)# engineR1(config-sigdef-sig-engine)# event-action produce-alertR1(config-sigdef-sig-engine)# event-action deny-packet-inlineR1(config-sigdef-sig-engine)# event-action reset-tcp-connectionR1(config-sigdef-sig-engine)# exitR1(config-sigdef-sig)# exitR1(config-sigdef)# exitDo you want to accept these changes? [confirm] yR1(config)#

This example shows how to change signature actions to alert, drop, and reset for signature 6130 with subsig ID of 10.

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Viewing Configured Signatures

Choose Configure > Intrusion Prevention > Edit IPS > Signatures > All Categories

Filter the signature list according to type

To modify a signature, right-click on the signature then choose an option from the pop-up

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Modifying Signature Actions

To tune a signature, choose Configure > Intrusion Prevention > Edit IPS > Signatures > All Categories

To modify a signature action, right-click on the signature and choose Actions

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Editing Signature Parameters

Choose the signature and click Edit

Different signatures have different parameters that can be modified:• Signature ID• Sub Signature ID• Alert Severity• Sig Description• Engine• Event Counter• Alert Frequency• Status

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5.4 Verify and Monitor IPS

Chapter Five


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Verify and Monitor IPS

• Verifying Cisco IOS IPS

• Monitoring Cisco IOS IPS

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5.4.1 Verifying Cisco IOS IPS

• Using CLI Commands to Verify

• Using SDM to Verify

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Using CLI Commands

The show ip ips privileged EXEC command can be used with several other parameters to provide specific IPS information.

• The show ip ips all command displays all IPS configuration data.

• The show ip ips configuration command displays additional configuration data that is not displayed with the show running-config command.

• The show ip ips interface command displays interface configuration data. The output from this command shows inbound and outbound rules applied to specific interfaces.

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Using CLI Commands

• The show ip ips signature verifies the signature configuration. The command can also be used with the key word detail to provide more explicit output

• The show ip ips statistics command displays the number of packets audited and the number of alarms sent. The optional reset keyword resets output to reflect the latest statistics.

Use the clear ip ips configuration command to remove all IPS configuration entries, and release dynamic resources. The clear ip ips statistics command resets statistics on packets analyzed and alarms sent.

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Using SDM

Choose Configure > Intrusion Prevention > Edit IPS

All of the interfaces on the router displayshowing if they are enabled or disabled

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5.4.2 Monitoring Cisco IOS IPS

• Reporting IPS Intrusion Alerts

• SDEE on an IOS IPS Router

• Using SDM to View Messages

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Reporting IPS Intrusion Alerts

• To specify the method of event notification, use the ip ips notify [log | sdee] global configuration command.

- The log keyword sends messages in syslog format.

- The sdee keyword sends messages in SDEE format.

R1# config tR1(config)# logging 192.168.10.100R1(config)# ip ips notify logR1(config)# logging onR1(config)#

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SDEE on an IOS IPS Router

• Enable SDEE on an IOS IPS router using the following command:

• Enable HTTP or HTTPS on the router

• SDEE uses a pull mechanism

• Additional commands:

-ip sdee events events

-Clear ip ips sdee {events|subscription}

-ip ips notify

R1# config tR1(config)# ip http serverR1(config)# ip http secure-serverR1(config)# ip ips notify sdeeR1(config)# ip sdee events 500R1(config)#

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Using SDM to View Messages

To view SDEE alarm messages, choose Monitor > Logging > SDEE Message Log

To view Syslog messages, choose Monitor > Logging > Syslog

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Documents

1 CCNA Security Chapter Five Implementing Intrusion Prevention